Question

the mean weitht of 34 student of class9 of a school is 42 kg if , the weight of the ther be included,the mean rises by 400hund gm find the weight of the teacher  

Answer 1

let the weight of all students = x
then x/34 = 42
hence x = 42*34 = 1428....................................(i)
if teacher's(t) weight is included then 
                                         (x+ t) / 35 = 42.4kg
substituting the value of x from (i),
 we get,              1428 + t = 42.4 * 35 
                          which emplies, 1428 + t = 1484
            hence t = 1484-1428 = 56kg